The present invention relates to high-power electrical switches, and in particular to a flexible cable assembly for remotely actuating electrical switches such as circuit breakers.
High-power electrical circuitry is normally placed inside a metal cabinet to protect the electrical circuitry from the external environment and to shield users from potential hazards associated with the operation of the circuitry.
Often the cabinet provides a handle that serves both to lock a cabinet door and to disconnect electrical power from the interior circuitry before the door is opened. The handle may communicate through a flexible cable assembly with a switch inside the cabinet, for example, a circuit breaker, so that when the handle is moved to allow opening of the cabinet door, the circuit breaker is also opened, removing electrical power from the interior circuitry. This feature is normally subject to the mechanical override in the event that the cabinet must be operated with the door open and the circuitry live.
A flexible cable assembly provides a substantially incompressible sheath through which a flexible cable may slide. Opposite ends of the sheath are fixed, respectively, to a stationary structure of the handle and an actuator frame attached to the circuit breaker housing. One end of the flexible cable is then attached to a movable portion of the handle to communicate this motion through the flexible cable to a slider held within the actuator frame. The slider may provide a collar capturing a toggle operator of the circuit breaker to move the circuit breaker toggle between an “on” and “of” position with movement of the flexible cable by the handle.
When it is necessary to work on equipment controlled by the circuitry within the cabinet, it is known to move the handle to the “off” position thereby disconnecting electrical power to the interior circuitry as described above. The handle normally provides a locking feature allowing insertion of a padlock or the like through portions of the handle preventing the handle from being moved from the “off” position to the “on” position. While the electrical power is thereby removed from the interior circuitry, this state of the handle allows opening of the cabinet door such as may allow access to the interior circuitry. Such access could allow inadvertent reactivation of the circuit breaker, for example, by damage or disconnection of the flexible cable, risking unexpected machine activation.